# include <stdio.h>
# define N a
int a,k;
int age (int n)
{
	if(n==1)
	  return N;
	  return age(n-1)+k;
}
	int main()

   {
   	int n;
	scanf("%d%d%d",&n,&a,&k);
	if(a>100||k>100||n<2)
	printf("Wrong Number\n");
	
	else
	printf("%d\n",age(n));
	
	return 0;
   }
